Yew (thing)

Lines left upon a seat in a yew-tree,
which stands near the Lake of Esthwaite,
on a desolate part of the shore, commanding a beautiful prospect.
Nay, Traveller! rest. This lonely Yew-tree stands
Far from all human dwelling: what if here
No sparkling rivulet spread the verdant herb?
What if the bee love not these barren boughs?
Yet, if the wind breathe soft, the curling waves,
That break against the shore, shall lull thy mind
By one soft impulse saved from vacancy.
---from “Lines Left Upon A Seat In A Yew-Tree”
by William Wordsworth

Maybe Wordsworth's yew tree was located in a desolate place, but humans have lived close to yew trees throughout history. For thousands of years, humans have found uses for live plants, foliage, wood, and tiny fruit of this slow-growing, long-lived shrub. Recently, the bark has also become prized as medicine.

The yew bush or tree includes several species native across Europe, Asia, North America, Africa and some Pacific islands. If you're looking at the landscaping, it's probably the common or European yew (taxus baccata) or Canadian yew (taxus canadensis). Each of this large group is well-adapted to live in nearly all climates, and can thrive even in poor soils in climates with harsh winters. The plants can grow upwards of 15.24 meters(50 feet) tall, with thick branches and needle-like leaves approximately 1.5-4 centimeters long and 0.3-0.2 centimeters wide. Yews are legendary for their long life, with individuals estimated at up to 2,000-4,000 years old. There are some reports of individuals surviving to 5,000-9,500 years, but highly branched trunks prevent counting growth rings in these ancient specimens.

Yew reproduces through small seeds produced in the spring from tiny flowers growing between leaves. Most individuals are dioecious, and bear either female or male flowers on each plant. Occasionally, monoecious individuals bear both female and male flowers, or change between dioecious and monoecious. Both female and male flowers are tiny, with female flowers measuring 4-7 millimeters in diameter. Male pollen cones measure 3–6 millimeters. Fertilized female flowers grow quickly into aril-covered fruits, which grow first as a green seed that turns brown. These red, berry-like fruits only grow up to 0.31–0.59 in 8–15 millimeters. Later, the green aril which partially surrounds the round seed and ripens into a fragile, fleshy pulp. This sugar, y surrounding gives the fruit the impression of a brown pebble mashed into red clay, or a brown marble lodged in a bellybutton. While the inner seed is highly toxic and loaded with heart-slowing taxanes, the red pulp surrounding the seed contains no poisons and can be eaten safely by both animals and humans. The fruit pulp of the aril has a smooth, syrupy texture and is very sweet with a faint pine taste. When birds eat the highly visible fruits, the seed passes through them intact without harming the passenger or carrier. Birds are the main way for seeds to disperse long distances.

While humans can consume the berry-like fruits safely if they spit out the seeds, you will never find them for sale. Aside from bearing potentially lethal seeds, the fruits are too small and fragile to offer much interest. Still, there is at least one recipe for a yew berry tart. Yew is one fruit you'll never see at the store, no matter how exotic their other offers are. There are too many other plants with edible arils, like pomegranate. While the pomegranate appears to be a single globe with a seedy flesh, every sweet mouthful is actually a collection of fruits, each surrounded by a juicy aril. Newly introduced to world markets in juices and supplements, the mangosteen is another fruit grown and marketed for its tasty aril. Tamarinds make a great paste featured in many Indian and south Asian dishes. Adventurous foragers and knowledgeable locals can snack on lesser-known fruits like the Jamaican Ackee, quamachil, balsam apple and tuckeroo.

While its slow growth and irregularly shaped branches preclude the trees from serving as main structures, the tough elastic wood is useful where a smaller volume of wood will do. Yew finds many uses in ancient weaponry. The oldest discovered use is a yew spear head, found the UK and is estimated at 450,000 years old. In medieval Wales and England, yew wood was ideal for the longbow, a powerful weapon that could send an arrow through even armored fighters. Some longbows had draw pulls topping 670–900 N (150–200 pounds). Since they can be winched into place or pulled with an archer's abdominal muscles, crossbows or arbalests with yew bows could top even these impressive draw pulls. Vikings also used the highly resinous wood as pegs or nails to secure warships together. While the wood would be useful as structural slats, the rarity of straight pieces prevented them from using yew as more than a fastener in shipbuilding.

Ancient humans discovered that yew could heal as well as kill. Avicenna introduced an herbal drug he named "Zarnab" as a cardiac remedy in The Canon of Medicine. In the Central Himalayas, the plant treats breast and ovary cancers. Likewise, the chemotherapy drugs paclitaxel (taxol) and docetaxel are derived from the bark of the Pacific Yew (Taxus brevifolia). Unfortunately, this requires killing the slow-growing and endangered trees. Fortunately, the drugs can also be synthesized by converting precursors from the leaves of common or European yew.

Yew has made ideal landscaping for hundreds of years. It tolerates both heat and cold, flood and drought, and is incredibly long-lived. Its wiry, resilient branches retain their shape which make them perfect for shaping into topiary, including rounded or geometric forms, exotic animal shapes and even mazes. Unlike other conifers like juniper, the leaves are smooth and do not prick when touched. This simplifies pruning, and allows lost wanderers to squeeze their way through walls which would otherwise deter shortcuts.

Lastly, the foliage is toxic to livestock like horses, cows, sheep and pigs. This may have endeared it to persnickety parsons hoping to discourage wandering livestock from loitering around their houses of worship. Yews surround many old churches in Europe and their branches may have also provided substitutes for otherwise unavailable palm fronds for celebrating Easter. This combination of qualities made them an ideal landscaping for churches, providing utility for guests and a repellent for four-footed trespassers.